JP4819244B2 - Plasma processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus that generates a plasma and performs a predetermined process.
[0002]
[Prior art]
In the manufacture of semiconductor devices and flat panel displays, plasma processing apparatuses are frequently used to perform processes such as oxide film formation, semiconductor layer crystal growth, etching, and ashing. An example in which this plasma processing apparatus is applied to an etching apparatus will be described. FIG. 9 is a diagram showing a configuration example of an etching apparatus using a conventional plasma processing apparatus.
In the processing chamber 511, a susceptor 521 having a mounting surface on which the wafer W is placed, and an upper electrode 531 are arranged in parallel to the mounting surface of the susceptor 521. The susceptor 521 also serves as a lower electrode.
An exhaust port 513 for exhausting the inside of the processing chamber 511 to a predetermined degree of vacuum is provided at the bottom of the processing chamber 511, and a gas for supplying process gas into the processing chamber 511 is provided on the side wall of the processing chamber 511. A supply nozzle 514 is provided.
[0003]
For example, a high frequency power source 534 that outputs high frequency power of 60 MHz is connected to the upper electrode 531 via a matching circuit 535. When the supply of high frequency power having a frequency of 60 MHz from the power source 534 to the upper electrode 531 is started, an electric field having a frequency of 60 MHz is formed in the space between the upper electrode 531 and the susceptor 521. This electric field ionizes the gas supplied from the nozzle 514 to generate plasma P, and this plasma P is used for etching the wafer W placed on the mounting surface of the susceptor 521.
[0004]
When performing the etching process, it is desirable that the distribution of the plasma P does not spread over the entire processing chamber 511 but is distributed at a high density on the mounting surface of the susceptor 521. This is because the etching process can be efficiently performed and the etching of the processing chamber 511 by the plasma P to the inner wall surface can be suppressed to extend the life of the processing chamber 511.
Therefore, in this etching apparatus, a filter 527 composed of an LC series resonance circuit is inserted between the susceptor 521 and the ground. The resonance frequency of the filter 527 is designed to be 60 MHz, which is the same as the frequency of the high frequency power supplied to the upper electrode 531. For example, by setting L = 0.07 μH and C = 100 pF, the resonance frequency of the filter 527 can be set to 60 MHz. The frequency characteristic of the filter 527 is as shown by a solid line in FIG. 10, and the impedance is minimum at 60 MHz.
[0005]
[Problems to be solved by the invention]
However, when the plasma P is generated, an ion sheath SH is formed between the plasma bulk and the upper electrode 531 or the susceptor 521. Since an electric field is formed in the layer of the ion sheath SH, a new capacity is generated between the upper electrode 531 and the susceptor 521 by the generation of the plasma P. For example, if a capacitance of 200 pF is generated by the sheath SH, the first path from the upper electrode 531 to the ground through the susceptor 521 and the filter 527 even if the resonance frequency of the filter 527 is designed to be 60 MHz as described above. The frequency characteristic is shown by a dotted line in FIG. 10, and the resonance frequency of the first path is 74 MHz. Therefore, even if the filter 527 is designed without considering the influence of the ion sheath SH as in the prior art, resonance does not occur at the frequency of the high-frequency power when the plasma P is generated, so that the impedance of the first path is made sufficiently small. I could not. For this reason, there is a problem that the plasma P cannot be sufficiently concentrated on the mounting surface of the susceptor 521.
[0006]
Further, when the process conditions such as the power value of the high-frequency power supplied to the upper electrode 531, the pressure in the processing chamber 511, the type of the process gas, or the mixing ratio are changed, the capacity of the ion sheath SH described above also changes. For this reason, even if the filter 527 is designed in consideration of the influence of the ion sheath SH that is generated when plasma is generated under a predetermined process condition, the filter 527 is designed to have a high frequency power frequency (for example, 60 MHz) under a different process condition. There was a problem that resonance could not be taken.
[0007]
Further, as described above, when the etching process is performed, it is better to distribute the plasma P intensively on the mounting surface of the susceptor 521. However, when the inside of the processing chamber 511 is cleaned, the plasma P is rather processed. It is better to diffuse it throughout the chamber 511. As described above, the preferable plasma distribution differs depending on the purpose of the processing. Conventionally, the filter 527 is designed for the etching process and the characteristics thereof are fixed. Therefore, the inside of the processing chamber 511 is cleaned under preferable conditions. There was a problem that I could not.
[0008]
Further, if the deposit attached to the inner wall surface of the processing chamber 511 is peeled off during the etching process and becomes particles, the particles adhere on the wafer W, causing a reduction in yield of elements formed on the wafer W. Accordingly, it is desirable that deposits do not adhere to the inner wall surface of the processing chamber 511 at all, or adhere stably so that they do not peel off during the process even if they adhere. However, the adhesion state of the deposit varies depending on the process conditions as described above. For this reason, when processing is performed by changing the process conditions, the adhesion state of the deposit is changed to generate particles, and the yield may decrease due to the particles.
The above problem is not limited to the case where the plasma processing apparatus is applied to the etching apparatus, but is a problem common to the plasma processing apparatus.
[0009]
The present invention has been made to solve such problems, and an object thereof is to realize a preferable plasma distribution according to the purpose of the plasma treatment.
[0010]
[Means for Solving the Problems]
  In order to achieve such an object, the present invention provides:AirtightPlace the object to be processed in the processing chamberA lower electrode having a mounting surface; an upper electrode disposed in the processing chamber and facing the mounting surface of the lower electrode; a high-frequency power source that generates an alternating electric field in the processing chamber to excite plasma; and the upper electrode and the high-frequency power source Matching circuit provided between and lower electrodeA first filter that is connected between the ground and the ground and whose circuit characteristics can be changed;,It is characterized by comprising a sensor for detecting the state of the plasma and a control means for controlling the circuit characteristic of the first filter based on the detection result output from the sensor. ThisBottom electrodeFrom an electric field generating means for generating an alternating electric field at a position opposite to the mounting surface ofBottom electrodeIn addition, the impedance of the first path that reaches the ground through the filter can be adjusted according to the state of the plasma.
  Here, the control means is for performing a process such as etching or CVD, for example.Bottom electrodeIn order to maximize the plasma distributed in the region facing the mounting surface of the first filter, it is preferable to control the circuit characteristics of the first filter in a direction in which the impedance of the first path becomes smaller (this mode is the first control). Called mode). In order to clean the inside of the processing chamber, when the plasma is diffused throughout the processing chamber and the plasma reaching the inner wall surface of the processing chamber is maximized, the impedance of the first path is increased. The circuit characteristics of the first filter may be controlled (this mode is referred to as the second control mode).
  By detecting the plasma state in this way and controlling the circuit characteristics of the first filter based on the detection result, plasma is generated and an ion sheath is formed, and even if the state of the ion sheath changes. The plasma distribution suitable for the plasma processing can be realized without being affected by the influence.
  In the case of a parallel plate type plasma processing apparatus, the electric field generating means isBottom electrodeThe counter electrode is arranged in parallel to the mounting surface of the first electrode and a power source for supplying high frequency power to the electrode. In addition, the sensor may be, for example, the value of the current flowing through the first filter, the value of the voltage applied to the first filter, the phase difference between the current and the voltage, the value of the current flowing through the counter electrode, and the voltage applied to the counter electrode. Any value may be used as long as it detects the phase difference between the current / voltage of the first filter and the current / voltage of the counter electrode. Also, the walls of the processing chamber (Bottom electrodeAnd the output signal of the sensor attached to the window may be used to control the first filter. These may be shared.
[0011]
The control means may include a switch for switching between the first control mode and the second control mode in multiple stages or arbitrarily. Since these two control modes can be realized by switching the switch, not only the processing such as etching but also the cleaning can be performed in a preferable state.
[0012]
The control means may realize a predetermined plasma distribution corresponding to each control mode in the processing chamber by switching a plurality of control modes. As a result, even if the process conditions are changed and the adhesion state of the deposit on the inner wall surface of the processing chamber changes, the amount of the plasma reaching the inner wall surface of the processing chamber is adjusted accordingly. It can suppress peeling and becoming particles.
Here, the control means may have a function of changing the circuit characteristics of the first filter during the process. For example, the amount of plasma that reaches the inner wall surface of the processing chamber may be periodically changed, or the amount of plasma that reaches the inner wall surface may be changed based on the temperature of the wall of the processing chamber. Thereby, the deposit adhering to the inner wall surface of the processing chamber can be stabilized.
[0013]
Further, when the sensor detects the value of the current flowing through the first filter, the control means, when the first control mode is selected, causes the current value of the first filter to increase. When the circuit characteristic is controlled and the second control mode is selected, the circuit characteristic of the first filter may be controlled in a direction in which the current value decreases.
In addition, when the sensor detects the value of the voltage applied to the first filter, the control means, when the first control mode is selected, causes the voltage of the first filter to decrease. When the circuit characteristic is controlled and the second control mode is selected, the circuit characteristic of the first filter may be controlled in a direction in which the voltage value increases.
[0014]
In addition, when the sensor detects the number of ions that reach a predetermined region of the inner wall surface of the processing chamber, the control means is configured to reduce the number of ions when the first control mode is selected. When the circuit characteristic of the first filter is controlled and the second control mode is selected, the circuit characteristic of the first filter may be controlled in a direction in which the number of ions increases.
The control means may control the circuit characteristics of the first filter in accordance with a value obtained by performing arithmetic processing on detection results output from a single sensor or a plurality of sensors. This makes it possible to perform more appropriate control than when the detection result is used for control as it is.
[0015]
  The present invention also provides:Bottom electrodeConnected toBottom electrodeAnd a second filter connected between the electric field generating means and the ground, the circuit characteristics of which can be changed, and the control means is output from the sensor. The circuit characteristic of the second filter may be controlled based on the detection result.Bottom electrodeThe energy and anisotropy of the plasma can be controlled by applying a bias between the electric field generating means and the electric field generating means. At this time,Bottom electrodeThe impedance of the second path from the first through the electric field generating means and the second filter to the ground can be adjusted according to the plasma state, so that plasma is generated and an ion sheath is formed, and the state of the ion sheath is changed. However, accurate control is possible without being affected by this.
  Here, the sensor is, for example, the value of the current flowing through the second filter, the value of the voltage applied to the second filter, the phase difference between the current and the voltage,Bottom electrodeValue of the current flowing throughBottom electrodeValue of the voltage applied to the current and voltage of the second filterBottom electrodeWhat is necessary is just to detect a phase difference from the current / voltage. Also, the walls of the processing chamber (Bottom electrodeAnd the output signal of the sensor attached to the window may be used to control the second filter. These may be shared.
[0016]
When the sensor detects the value of the current flowing through the second filter, the control means may control the circuit characteristics of the second filter in the direction in which the current value increases.
Further, when the sensor detects the voltage value applied to the second filter, the control means may control the circuit characteristics of the second filter in a direction in which the voltage value decreases.
In addition, when the sensor detects the number of ions that reach a predetermined region on the inner wall surface of the processing chamber, the control means controls the circuit characteristics of the second filter in a direction in which the number of ions decreases. May be.
The control means may control the circuit characteristics of the first and second filters in accordance with a value obtained by performing arithmetic processing on detection results output from a single sensor or a plurality of sensors. This makes it possible to perform more appropriate control than when the detection result is used for control as it is.
[0017]
The control means may appropriately control the circuit characteristics of the first filter so that the occurrence of abnormal discharge in the processing chamber is suppressed. Or you may make it control the circuit characteristic of a 1st and 2nd filter suitably so that generation | occurrence | production of abnormal discharge in a process chamber may be suppressed.
[0018]
The first filter may be configured to include an inductance of 5 μH or more or a capacitance of 1000 pF or less. Alternatively, the first and second filters may be configured to include an inductance of 5 μH or more or a capacitance of 1000 pF or less. As a result, even when the inductance and the capacitance due to the ion sheath change according to the process conditions, the first and second paths can be easily obtained with or without changing the circuit characteristics of the filter. Can be adjusted according to the state of the plasma.
[0019]
  Also,The present invention relates to a susceptor having a mounting surface that is placed in an airtight processing chamber and places an object to be processed, an electric field generating means that excites plasma by generating an alternating electric field at a position opposite to the mounting surface of the susceptor, and a susceptor The first filter connected between the ground and the ground, the circuit characteristics of which can be changed, a sensor for detecting the plasma state, and the control means for controlling the circuit characteristics of the first filter based on the detection result output from the sensor In the plasma processing apparatus including the first filter,A first module that blocks passage of a DC component; and a second module that can change a circuit constant corresponding to the frequency of the AC electric field.It is characterized by that.
In addition, the lower electrodeWhen the bias power source is connected to the first filter, the first filter may include a third module that blocks passage of the frequency component of the bias. In this case, the first filter may include a shielding plate that electrostatically or electromagnetically shields between the first and second modules and the third module. The second filter includes a first module that blocks passage of a DC component, a second module that can change a circuit constant with respect to a bias frequency, and a third module that blocks passage of a frequency component of a high-frequency electric field. A module may be included. In this case, the second filter may have a shielding plate that electrostatically or electromagnetically shields between the first and second modules and the third module.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a case where the present invention is applied to an etching apparatus will be described as an example.
(First embodiment)
FIG. 1 is a diagram showing the configuration of an etching apparatus according to the first embodiment of the present invention. In this figure, a cross-sectional structure is shown for a part of the configuration.
[0021]
The processing chamber 11 of this etching apparatus is formed in a cylindrical processing container 12 that can be closed airtight. The processing container 12 is made of a conductive material such as aluminum. An exhaust port 13 communicating with a vacuum pump (not shown) is provided at the bottom of the processing container 12 so that the processing chamber 11 can be set to a desired degree of vacuum.
A support base 22 is provided at the bottom of the processing container 12 via an insulating plate 23, and a columnar susceptor 21 is fixed on the support base 22. The susceptor 21 has a horizontal mounting surface for placing a wafer (object to be processed) W to be etched. The susceptor 21 also serves as a lower electrode and is made of a conductive material such as aluminum.
[0022]
In the upper space of the processing chamber 11, a disk-shaped upper electrode 31 provided with a plurality of through holes 31 </ b> A is disposed in parallel with the mounting surface of the susceptor 21. The upper electrode 31 is made of a conductive material such as single crystal silicon and is fixed to the lower portion of the support 32.
The support 32 is made of a conductive material such as aluminum, and forms a hollow cylinder inside with the upper electrode 31 as a bottom surface. The upper opening of the processing container 12 is attached via the insulating ring 33 so as to close the upper opening. A gas inlet 32A is provided at the center of the upper surface of the support 32, and a gas inlet tube 39 is connected to the gas inlet 32A. From this gas introduction pipe 39, Ar and O₂ Process gas such as is introduced.
[0023]
A high frequency power supply 34 is connected to the support 32 having the same potential as the upper electrode 31. The high frequency power supply 34 may be anything that outputs high frequency power having a frequency of about several tens of MHz and a power value of about 5 kW. Here, it is assumed that high frequency power having a frequency of 60 MHz and a power value of 3.3 kW is output. A matching circuit 35 for matching these impedances is connected between the high frequency power supply 34 and the support 32. The matching circuit 35 is composed of a variable capacitor, for example, and the capacity thereof is controlled by the controller 36.
[0024]
On the other hand, the susceptor 21 is grounded via a first filter 27 formed of a resonance circuit whose reactance can be changed. A path from the upper electrode 31 to the ground through the susceptor 21 and the filter 27 is referred to as a first path. By changing the reactance of the filter 27, the impedance of the first path with respect to the frequency (60 MHz) of the high frequency power supplied to the upper electrode 31 can be adjusted.
Further, a sensor 28 for detecting an electric signal flowing through the filter 27 based on the state of the plasma P generated in the processing chamber 11 and a control means for controlling the reactance of the filter 27 based on the detection result output from the sensor 28 are provided. It has been. In the etching apparatus shown in FIG. 1, the function of the control means of the filter 27 is provided to the controller 36 of the matching circuit 35, but the control means of the filter 27 may be provided separately.
[0025]
Here, the filter 27 will be further described.
FIG. 2 is a circuit diagram showing the configuration of the filter 27. The filter 27 includes a first module 27A that blocks the passage of a DC component, and a second module 27B that can change the reactance with respect to the frequency of the high-frequency power supplied to the upper electrode 31.
When high frequency power is supplied from the high frequency power supply 34 to the upper electrode 31, a DC voltage of about several hundred volts is generated in the susceptor 21. The first module 27A includes a capacitor 27p, for example, and can prevent a DC component from being short-circuited by preventing the DC component from passing from the susceptor 21 to the ground.
[0026]
On the other hand, the second module 27B includes, for example, a series circuit (LC series resonance circuit) of a coil 27r and a capacitor 27q. In this case, at least one of the inductance of the coil 27r and the capacitance of the capacitor 27q may be made variable. Here, the inductance of the coil 27r is variable, and the capacitance of the capacitor 27q is fixed. When the second module 27B is an LC series resonance circuit as shown in FIG. 2, the capacitor 27q of the second module 27B may also serve as the capacitor 27p of the first module 27A.
[0027]
The reactance composed of the inductance L of the filter 27 (that is, the inductance of the coil 27r) and the capacitance C (that is, the combined capacitance of the capacitors 27p and 27q) is the inductance L of the ion sheath SH._SHAnd capacity C_SHIn consideration of the structure of the processing vessel 12 and the electrodes (susceptor 21, upper electrode 31), the resonance frequency f of the first path under a predetermined process condition₁Is equal to the frequency (60 MHz) of the high-frequency power supplied to the upper electrode 31, and the impedance for the frequency is designed to be minimum. However, depending on the process conditions, the inductance L due to the ion sheath SH_SHAnd capacity C_SHOf the filter 27 so that the impedance of the first path can be minimized, and the impedance of the first path can be sufficiently increased when cleaning the inside of the processing chamber 11. A reactance range is set.
[0028]
For example, the filter 27 is designed under the following process conditions.
-Frequency of high frequency power: 60 MHz, power value: 1.0 to 5.0 kW
・ Processing pressure: 0.6 to 10 Pa
Process gas: Ar = 100 to 500 sccm, O₂ = 5-15sccm
(Sccm = standard cubic centimeter per minute)
Capacitance C due to the ion sheath SH generated when the plasma P is generated under these conditions_SHIs approximately 100-300 pF. On the other hand, the resonance frequency f of the first path including the filter 27₁Is expressed as follows.
f₁= 1 / [2π (LC₁)^1/2] (1)
C₁ = C ・ C_SH/ (C + C_SH)) (2)
C_SH= F for 200 pF₁In order to set = 60 MHz, C = 200 pF, 50 nH ≦ L ≦ 110 nH.
[0029]
Alternatively, the inductance L due to the ion sheath SH_SHFixed inductance L that is sufficiently larger than the upper limit of the fluctuation range, or capacitance C due to the ion sheath SH_SHThe filter 27 may be configured using a fixed capacitor C that is sufficiently smaller than the lower limit of the fluctuation range. In this case, for example, the fixed inductance L is preferably 5 μH or more and the fixed capacitance C is 1000 pF or less. Thereby, the inductance L due to the ion sheath SH according to the process conditions._SHAnd capacity C_SHEven if is changed, the reactance range of the filter 27 can be set so that the impedance of the first path can be minimized or sufficiently increased without being affected by the change.
Alternatively, the filter 27 may be configured by only the capacitor 27q, and the LC resonance circuit may be configured by using the inductance of the wiring that connects the susceptor 21 to the ground via the filter 27.
[0030]
Next, the sensor 28 will be further described.
FIG. 3 is a diagram illustrating a configuration of the sensor 28. The sensor 28 includes a high-frequency current sensor 28A that detects the value of the current flowing through the filter 27 and outputs it to the controller 36, and a high-frequency voltage sensor 28B that detects the value of the voltage applied to the filter 27 and outputs it to the controller 36. Has been.
By inserting a filter (not shown) that passes only 60 MHz on the output side of the current sensor 28A and the voltage sensor 28B, it is possible to accurately detect only the frequency of the high-frequency power supplied to the upper electrode 31.
[0031]
Next, the controller 36 as control means for the filter 27 will be further described.
When the sensor 28 includes the current sensor 28A and the voltage sensor 28B, the controller 36 calculates the power consumption value of the filter 27 by calculating the phase difference between the current and voltage detected by the sensor 28, and the detection. A function of controlling the reactance of the filter 27 based on the calculated current value or voltage value and the calculated power value. Alternatively, a high-frequency equivalent circuit of the processing container 12 is stored in the controller 36 in advance, and the current flowing to the susceptor 21 and the side wall of the processing container 12 is calculated based on the output of the filter 27, so that the reactance of the filter 27 is controlled. May be.
The reactance control of the filter 27 may be performed alone or in combination with the capacitance control of the matching circuit 35 according to a predetermined sequence.
[0032]
Further, the controller 36 controls the first control mode in which the plasma P distributed in the region facing the mounting surface of the susceptor 21 is maximized, and the plasma P reaching the inner wall surface of the processing chamber 11 is maximized. It has a switch (not shown) for switching between the second control mode to be controlled. The first control mode is selected when performing the etching process, and the second control mode is selected when performing the cleaning.
[0033]
When the first control mode is selected, the controller 36 controls the reactance of the filter 27 so that the impedance of the first path with respect to the frequency of the high-frequency power supplied to the upper electrode 31 is minimized. For example, the capacitance C of the filter 27 is controlled so that the value of the current passing through the filter 27 is maximized. When the second control mode is selected, the reactance of the filter 27 is controlled so that the impedance of the first path with respect to the frequency of the high-frequency power becomes sufficiently large. For example, the capacitance C of the filter 27 is controlled so that the value of the current passing through the filter 27 becomes sufficiently small.
[0034]
As described above, the control may be performed based on the value of the current passing through the filter 27 itself. However, the current flowing from the susceptor 21 to other members such as an insulator (not shown) and the circuit is also taken into consideration. It is preferable to estimate and control the total current incident on the.
Note that the reactance of the filter 27 may be controlled so that the value of the voltage applied to the filter 27 is increased or decreased.
[0035]
As described above, the detection result output from the sensor 28 may be used for control as it is, such as the detected current value or voltage value, but the detection result is obtained by applying the calculation result to a predetermined model. Values may be used for control. The model here is, for example, a calculation formula for calculating an index indicating the plasma distribution in the processing chamber 11 from the value of the current passing through the filter 27. By using this model, more appropriate control is possible.
[0036]
Next, the operation of the etching apparatus shown in FIG. 1 will be described.
The operation during the etching process will be described.
First, with the wafer W placed on the mounting surface of the susceptor 21, the inside of the processing chamber 11 is evacuated to about 2.7 Pa, for example. While maintaining this degree of vacuum, Ar and O are introduced into the space between the support 32 and the upper electrode 31 from the gas introduction pipe 39.₂ Are introduced at a flow rate of 400 sccm, respectively. This gas expands the space and is supplied into the processing chamber 11 from a plurality of through holes 31 </ b> A provided in the upper electrode 31. At this time, the gas supplied into the processing chamber 11 is uniformly discharged onto the processing surface of the wafer W.
[0037]
In this state, high frequency power having a frequency of 60 MHz and a power value of 3.3 kW is supplied from the high frequency power supply 34 to the upper electrode 31. This high-frequency power forms an AC electric field having a frequency of 60 MHz in the processing chamber 11, and goes out to the ground from the susceptor 21 or the processing container 12. The electric field formed in the processing chamber 11 ionizes the gas supplied into the processing chamber 11 to generate plasma P. At this time, an ion sheath SH with an electric field is formed on the outer periphery of the plasma P, and a capacity C of about 200 pF is newly provided between the upper electrode 31 and the susceptor 21 by the ion sheath SH._SHOccurs.
[0038]
Waiting for the plasma P to stabilize, the sensor 27 detects the value of the current flowing through the filter 27 interposed between the susceptor 21 and the ground and the value of the voltage applied to both ends of the filter 27, and sends it to the controller 36. Output. The controller 36 calculates a power value from the detected current value and voltage value. Since the controller 36 selects the first control mode suitable for the etching process, the controller 36 controls the reactance of the filter 27 in the direction in which the detected current value increases, so that the upper electrode 31 and the susceptor 21 and The impedance of the first path from the filter 27 to the ground is reduced.
[0039]
FIG. 4 is a diagram showing the frequency characteristics of the first path including the filter 27, and shows the resonance frequency f.₁The characteristic that is 60 MHz is indicated by a solid line, and the characteristic that is 74 MHz is indicated by a broken line. As can be seen from this figure, the impedance of the first path with respect to 60 MHz is the resonance frequency f of the first path.₁Is the minimum when 60 MHz. Therefore, the capacitance C of the filter 27 is controlled so that the resonance frequency of the first path is 60 MHz. The capacity C of the filter 27 is 200 pF, and the capacity C is about 100 to 300 pF due to the influence of the ion sheath SH._SHIn a situation where the occurrence of the noise occurs, the inductance L of the filter 27 is adjusted in the range of about 50 to 110 nH, as can be seen from the equations (1) and (2).
The detection by the sensor 28 and the control of the filter 27 by the controller 36 based on the detection result may be fixed after being performed once, or may be repeatedly performed as needed.
[0040]
As described above, the ratio of the high-frequency power supplied to the upper electrode 31 toward the processing container 12 is controlled by controlling the impedance of the first path to 60 MHz to be minimum based on the current passing through the filter 27. However, the ratio toward the susceptor 21 is further increased. As a result, the distribution of the plasma P generated by the high frequency power does not spread over the entire processing chamber 11 but concentrates on the mounting surface of the susceptor 21, so that the etching process of the wafer W using the plasma P is performed more than before. It can be done efficiently. In addition, since the plasma P reaching the inner wall surface of the processing container 12 is reduced as compared with the prior art, the etching of the plasma P on the inner wall surface of the processing container 12 can be suppressed, and the life of the processing container 12 can be extended. Can be reduced.
[0041]
Next, the case where the etching process is performed under different process conditions will be described. For example, the process conditions are changed as follows.
・ High frequency power frequency: 60 MHz, power value: 1.0 to 1.5 kW
・ Processing pressure: 2.7 Pa
Process gas: Ar = 300 to 400 sccm, O₂ = 5-20sccm
Under this condition, the capacity C of about 300 to 400 pF is obtained by the ion sheath SH._SHTherefore, the resonance frequency of the first path is set to 60 MHz by adjusting the inductance L of the filter 27 in the range of about 50 to 60 nH by the same control as described above, and the first frequency with respect to 60 MHz is adjusted. The impedance of the path can be minimized. Accordingly, even when the process condition is changed and the state of the ion sheath SH is changed, a plasma distribution suitable for the etching process can be realized without preparing a filter designed for the process condition.
[0042]
Next, cleaning inside the processing chamber 11 will be described. The operations from the generation of plasma P to the calculation of the power consumption value of the filter 27 are the same as in the etching process.
When cleaning is performed, since the second control mode is selected in the controller 36, the controller 36 controls the reactance of the filter 27 in a direction in which the detected current value decreases, and the susceptor from the upper electrode 31 is controlled. The impedance of the first path that reaches the ground via 21 and the filter 27 is increased.
[0043]
As can be seen from FIG. 4, the impedance of the first path with respect to 60 MHz is the resonance frequency f of the first path.₁Increases as the distance from 60 MHz increases. Therefore, here, the inductance L of the filter 27 is controlled so that the resonance frequency of the first path is far away from 60 MHz (excitation frequency). The resonance of the first path may be brought to a high frequency or a low frequency.
[0044]
As described above, the ratio of the high frequency power supplied to the upper electrode 31 toward the susceptor 21 is reduced by controlling the impedance of the first path with respect to 60 MHz to be large based on the current passing through the filter 27. However, the ratio toward the processing container 12 increases. As a result, the distribution of the plasma P generated by the high frequency power spreads throughout the processing chamber 11 and the plasma P reaching the inner wall surface of the processing chamber 11 increases, so that the inside of the processing chamber 11 can be efficiently cleaned. it can.
Thus, since the controller 36 can switch between the two control modes by the switch, not only the etching process but also the cleaning can be performed in a preferable state.
[0045]
In the etching apparatus shown in FIG. 1, the voltage sensor 28 </ b> B may detect the value of the voltage applied only to the capacitors 27 p and 27 q or the coil 27 r that are part of the filter 27.
Further, the sensor 28 may be configured by only the current sensor 28A. In this case, the controller 36 controls the reactance of the filter 27 so that the value of the current flowing through the filter 27 increases or decreases. Also in this case, it is preferable to estimate and control the total current incident on the susceptor 21.
The reactance of the filter 27 can be changed. However, it is sufficient that the circuit characteristics including the resistance can be changed.
Further, in order to minimize the impedance of the first path, it is not always necessary to use the resonance frequency, and as long as the impedance can be minimized as a result.
[0046]
(Second Embodiment)
FIG. 5 is a diagram showing a configuration of an etching apparatus according to the second embodiment of the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
The etching apparatus shown in FIG. 5 is a four-electrode mass spectrometer (hereinafter abbreviated as QMS) 29 installed on the inner wall surface of the processing vessel 12 as a sensor for detecting the state of the plasma P generated in the processing chamber 11. Is used. The QMS 29 detects the number of plasma ions that reach a predetermined region on the inner wall surface of the processing vessel 12.
[0047]
The detection result by the QMS 29 is output to the controller 36A. The controller 36A has the same function as the controller 36 shown in FIG. 1 except that the reactance of the filter 27 is controlled based on the detection result by the QMS 29 installed on the inner wall surface of the processing container 12.
When the first control mode suitable for the etching process of the wafer W is selected, the controller 36A performs filtering in such a direction that the number of ions detected by the QMS 29, that is, the number of ions reaching the inner wall surface of the processing container 12 decreases. 27 reactances are controlled. As a result, the plasma P does not spread over the entire processing chamber 11 but is distributed at a high density in a region facing the mounting surface of the susceptor 21. Therefore, as in the etching apparatus shown in FIG. This can be performed more efficiently than before, and the life of the processing vessel 512 can be extended.
[0048]
When the second control mode suitable for cleaning the inside of the processing chamber 11 is selected, the controller 36A increases the number of ions detected by the QMS 29, that is, the number of ions reaching the inner wall surface of the processing chamber 11. The reactance of the filter 27 is controlled in the direction. Thereby, the inside of the processing chamber 11 can be efficiently cleaned.
Instead of the QMS 29, a current sensor that detects the value of the current that flows from the processing container 12 to the ground may be used. In this case, the controller tends to decrease the current value detected by the current sensor in the first control mode and increase the current value detected by the current sensor in the second control mode. The reactance of the filter 27 may be controlled.
[0049]
The etching apparatus shown in FIG. 1 controls the filter 27 on the basis of an electrical signal that goes from the susceptor 21 to the ground. The etching apparatus shown in FIG. 5 uses the electrical signal that goes from the processing container 12 to the ground. Although the filter 27 is controlled, the filter 27 may be optimally controlled based on two electric signals by combining the both.
[0050]
(Third embodiment)
FIG. 6 is a diagram showing a configuration of an etching apparatus according to the third embodiment of the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
[0051]
The etching apparatus shown in FIG. 6 has a high frequency power for supplying a high frequency power for applying a bias between the upper electrode 31 and the susceptor 21 in addition to a high frequency power source 34 for supplying a high frequency power for exciting the plasma P. A two-frequency etching apparatus having a power source 24. By applying a bias between the upper electrode 31 and the susceptor 21, etching can be performed while controlling the energy and anisotropy of the plasma P. The high frequency power supply 24 only needs to output a high frequency power having a frequency of about 100 kHz to 13 MHz and a power value of about 1.0 to 5.0 kW. Here, it is assumed that high frequency power having a frequency of 2 MHz and a power value of 1.5 kW is output. At the time of cleaning, the output of the high frequency power supply 24 is stopped or becomes a low power output of 100 to 500 W.
The high frequency power supply 24 is connected to the susceptor 21 through a matching circuit 25. The matching circuit 25 matches impedances of the high-frequency power source 24 and the susceptor 21 and is composed of, for example, a variable capacitor, and its capacity is controlled by the controller 26.
[0052]
On the other hand, the support 32 having the same potential as the upper electrode 31 is grounded via a second filter 37 formed of a resonance circuit whose reactance can be changed. A path from the susceptor 21 to the ground through the upper electrode 31, the support 32, and the filter 37 is referred to as a second path. By changing the reactance of the filter 37, the impedance of the second path with respect to the frequency (2 MHz) of the high-frequency power supplied to the susceptor 21 can be adjusted.
[0053]
Further, a sensor 38 for detecting an electric signal flowing through the filter 37 and a control means for controlling the reactance of the filter 37 based on the detection result output from the sensor 38 are provided. In the etching apparatus shown in FIG. 6, the function of the control means of the filter 37 is given to the controller 26 of the matching circuit 25.
The sensor 38 and the controller 26 are configured similarly to the sensor 28 and the controller 36 shown in FIG. 1, respectively, and have the same functions. However, the controller 26 as the control means of the filter 37 only needs to have a function of controlling the reactance of the filter 37 in a direction in which the impedance of the second path with respect to the frequency of the high-frequency power supplied to the susceptor 21 decreases. .
[0054]
Here, the filter 37 will be further described.
FIG. 7 is a circuit diagram showing the configuration of the filter 37. The filter 37 includes a first module 37A that blocks the passage of a DC component, a second module 37B that can change reactance with respect to the frequency of the high-frequency power supplied to the susceptor 21, and a high-frequency that is supplied to the upper electrode 31. And a third module 37C that prevents passage of power frequency (60 MHz).
When high frequency power is supplied from the high frequency power supply 24 to the susceptor 21, a DC voltage of about several hundred volts is generated at the upper electrode 31. The first module 37A includes, for example, a capacitor 37p, and can prevent a DC component from being short-circuited by preventing the DC component from passing from the upper electrode 31 to the ground.
[0055]
Further, the second module 37B is configured by, for example, a series circuit (LC series resonance circuit) of a coil 37r and a capacitor 37q. In this case, at least one of the inductance of the coil 37r and the capacitance of the capacitor 37q may be made variable. Here, the inductance of the coil 37r is variable, and the capacitance of the capacitor 37q is fixed. When the second module 37B is an LC series resonance circuit as shown in FIG. 7, the capacitor 37q of the second module 37B may also serve as the capacitor 37p of the first module 37A.
Further, the third module 37C is constituted by a parallel circuit of, for example, a coil 37t and a capacitor 37s, and is designed to have a high impedance near the frequency (60 MHz) of the high-frequency power supplied to the upper electrode 31. . Thereby, inflow of the high frequency power supplied to the upper electrode 31 to the filter 37 can be prevented.
[0056]
Between the first and second modules 37A and 37B and the third module 37C, an aluminum or iron shielding plate 37D for electrostatic shielding or electromagnetic shielding is disposed. When electrical interference occurs between the third module 37C and the first and second modules 37A and 37B, the band blocking capability of the third module 37C is greatly reduced, and power loss due to the filter 37 occurs. As a result, the power efficiency is lowered, and in some cases, an excessive current flows through the filter 37 and the filter 37 may be burned out. By providing the shielding plate 37D, such a problem can be prevented.
[0057]
The reactance of the filter 37 having such a configuration is the resonance frequency f of the second path under a predetermined process condition.₂Is equal to the frequency (2 MHz) of the high-frequency power supplied to the susceptor 21, and the impedance for the frequency is designed to be minimum. Inductance L due to ion sheath SH depending on process conditions_SHAnd capacity C_SHSimilarly to the filter 27 shown in FIG. 1, the reactance range is set so that the impedance of the second path can be minimized even when the value changes.
[0058]
For example, under the process conditions:₂In order to set = 2 MHz, C = 1500 pF, 1 μH ≦ L ≦ 50 μH may be set.
・ High frequency power supplied to the upper electrode 31
Frequency: 60 MHz, power value: 1.0-5.0 kW
・ High frequency power supplied to the susceptor 21
Frequency: 2MHz, power value: 1.0-5.0kW
・ Processing pressure: 0.6 to 10 Pa
Process gas: Ar = 200 to 400 sccm, O₂ = 5-20sccm
Alternatively, the inductance L due to the ion sheath SH_SHFixed inductance L (for example, 5 μH or more) that is sufficiently larger than the upper limit of the fluctuation range, or capacitance C by the ion sheath SH_SHThe filter 37 may be configured using a fixed capacitance C (for example, 200 pF or less) that is sufficiently smaller than the lower limit of the fluctuation range.
[0059]
Note that the filter 127 includes the first and second modules 27A, 27A and 2B shown in FIG. 2 so that the 2 MHz high frequency power supplied from the high frequency power supply 24 to the susceptor 21 does not flow into the filter 127 connected to the susceptor 21. 27B has a configuration in which a third module (not shown) that blocks passage of a frequency of 2 MHz is connected in series. In this case, the reactance of the filter 127 is the resonance frequency f of the entire first path including the third module.₁Is designed to be equal to the frequency (60 MHz) of the high-frequency power supplied to the upper electrode 31. In addition, by disposing an aluminum or iron shielding plate that performs electrostatic shielding or electromagnetic shielding between the first and second modules 27A and 27B and the third module, power efficiency is reduced. Burnout can be prevented.
Further, as shown in FIG. 8, a matching circuit 125 including a filter 127 may be used.
[0060]
By providing the etching apparatus with the above-described configuration and controlling the impedance of the entire second path to be reduced to 2 MHz based on the current passing through the filter 37, the processing container of the high-frequency power supplied to the susceptor 21 is controlled. The ratio toward 12 decreases and the ratio toward the upper electrode 31 increases. Thereby, the energy and anisotropy of the plasma P by bias application can be controlled more accurately than in the past. Even when the process condition is changed and the state of the ion sheath SH changes, the energy and anisotropy of the plasma P can be controlled with the same accuracy.
Since the bias applied between the upper electrode 31 and the susceptor 21 may be a direct current or a pulse bias, a direct current power source may be used instead of the high frequency power source 24. Further, as a sensor for detecting the state of the plasma P, a sensor installed on the inner wall surface of the processing vessel 12 such as QMS shown in FIG. 5 may be used.
[0061]
(Fourth embodiment)
The controller 36 shown in FIG. 1 may have a plurality of control modes for realizing different plasma distributions in the processing chamber 11, and may have a switch (not shown) for switching between these control modes.
For example, in a process in which there are many deposits adhering to the inner wall surface of the processing container 12, the control mode in which the amount of plasma P reaching the inner wall surface of the processing container 12 increases is selected and the reactance of the filter 27 is controlled. This makes it difficult for deposits to adhere to the inner wall surface.
[0062]
On the other hand, in a process where the amount of deposits adhering to the inner wall surface of the processing container 12 is small, the control mode in which the amount of plasma P reaching the inner wall surface of the processing container 12 is smaller than that described above is selected to control the reactance of the filter 27 . In this case, the amount of arrival of plasma P may be relatively large so that no deposits adhere to the inner wall surface, or the amount of arrival of plasma P may be relatively large so that deposits adhere stably to the inner wall surface. It may be less.
Therefore, when the process conditions are changed, the control mode is switched according to the characteristics of the process, and the amount of deposits adhering to the inner wall surface of the processing container 12 is adjusted, so that the deposits are separated and generated. Particles can be reduced. Thereby, the yield of the elements formed on the wafer W can be improved.
[0063]
Further, the controller 36 shown in FIG. 1 may have a function of changing the reactance of the filter 27 during the etching process.
For example, the amount of plasma P that reaches the inner wall surface of the processing container 12 may be periodically changed during the process so that deposits attached to the inner wall surface of the processing container 12 are controlled to be stable.
Further, deposits that adhere to the inner wall surface of the processing container 12 are less likely to adhere when the temperature of the inner wall surface increases. For this reason, the temperature of the inner wall surface of the processing container 12 is measured so that the deposit adheres stably, and the amount of plasma P reaching the inner wall surface is changed during the process based on the measured temperature. It may be. Alternatively, the elapsed time from the start of plasma P generation may be measured, and similar control may be performed based on the measured time.
As described above, by stabilizing the deposit attached to the inner wall surface of the processing container 12, it is possible to prevent the deposit from peeling off and becoming particles. Thereby, the yield of the elements formed on the wafer W can be improved.
[0064]
Further, by changing the reactance of the filter 27 during the etching process, the amount and quality of radicals adhering to the inner wall surface of the processing container 12 can be changed. When the amount and quality of radicals adhering to the inner wall surface change, the components and amounts that desorb from the inner wall surface change. Therefore, the process performance can be improved by selecting the optimum radical.
Moreover, the radical composition in the processing chamber 11 changes at the etching end point, and the ease of attachment of radicals to the inner wall surface and the ease of separation from the inner wall surface change. Therefore, as one of the process conditions, the reactance of the filter 27 may be changed so that the radical composition does not change at the etching end point.
[0065]
The reactance control of the filter 27 by the controller 36 may be performed according to a preset procedure, or may be performed based on a detection signal such as an EPD (End Point Detection) signal indicating an etching end point. It may be.
The above functions of the controller 36 may be provided as functions for the filter 37 in the controller 26 shown in FIG.
[0066]
(Fifth embodiment)
The controller 36 shown in FIG. 1 may have a function of appropriately controlling the reactance of the filter 27 so that the occurrence of abnormal discharge in the processing chamber 11 is suppressed.
For example, the larger the value of the current flowing through the filter 27, the less likely abnormal discharge occurs. Accordingly, the value of the current flowing through the filter 27 is detected by the high-frequency current sensor 28A, the reactance of the filter 27 is controlled by the controller 36 in the direction in which the detected current value increases, and the current value is maximized. The occurrence of discharge can be suppressed.
[0067]
Further, the reactance control of the filter 27 may be performed based on the value of the voltage applied to the filter 27 instead of the value of the current flowing through the filter 27.
Whether or not the adjustment value is effective for suppressing abnormal discharge, such as the maximum value of the current flowing through the filter 27, can be known from the detection result of the sensor 28.
The function of the controller 36 may be given to the controller 26 shown in FIG.
[0068]
The parallel plate etching apparatus has been described above as an example, but the present invention can also be applied to an inductively coupled plasma etching apparatus, a microwave plasma etching apparatus, and the like. Needless to say, the present invention may be applied not only to the etching apparatus but also to other plasma processing apparatuses such as a plasma CVD apparatus.
[0069]
【The invention's effect】
As described above, in the plasma processing apparatus of the present invention, the sensor for detecting the plasma state, and the control means for controlling the circuit characteristics of the first filter connected between the susceptor and the ground according to the detection result. It has. Thereby, the impedance of the first path from the electric field generating means for generating an AC electric field at the position opposite to the mounting surface of the susceptor to the ground through the susceptor and the filter can be adjusted according to the state of the plasma. For this reason, the preferable plasma distribution according to the objective of plasma processing is implement | achieved, and processing efficiency can be improved. In addition, etching of the inner wall surface of the processing chamber due to plasma can be suppressed to extend the life of the processing chamber, and generation of particles can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an etching apparatus according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a configuration of a first filter.
FIG. 3 is a diagram showing a configuration of the sensor shown in FIG. 1;
FIG. 4 is a diagram illustrating frequency characteristics of a first path from an upper electrode to ground through a susceptor and a filter.
FIG. 5 is a diagram showing a configuration of an etching apparatus according to a second embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of an etching apparatus according to a third embodiment of the present invention.
FIG. 7 is a circuit diagram showing a configuration of a second filter.
FIG. 8 is a diagram showing a configuration in which a first filter and a matching circuit are integrally formed.
FIG. 9 is a diagram showing a configuration example of an etching apparatus using a conventional plasma processing apparatus.
10 is a diagram showing frequency characteristics of a filter used in the etching apparatus shown in FIG. 9, and frequency characteristics of a path from an upper electrode to a ground through a susceptor and a filter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Processing chamber, 12 ... Processing container, 21 ... Susceptor, 24, 34 ... High frequency power supply, 26, 36, 36A ... Controller, 27, 37, 127 ... Filter, 27A, 27B, 37A-37C ... Module, 37D ... Shielding Plate, 28, 38 ... Sensor, 29 ... QMS, 31 ... Upper electrode, P ... Plasma, SH ... Ion sheath, W ... Wafer.

Claims (22)

A lower electrode having a mounting surface disposed in an airtight processing chamber and on which an object to be processed is placed;
An upper electrode disposed in the processing chamber and facing a mounting surface of the lower electrode;
A high frequency power supply you exciting a plasma by generating an alternating electric field in the processing chamber,
A matching circuit provided between the upper electrode and the high-frequency power source;
A first filter connected between the lower electrode and the ground, the circuit characteristics of which can be changed;
A sensor for detecting the state of the plasma;
And a control means for controlling circuit characteristics of the first filter based on a detection result output from the sensor. The plasma processing apparatus according to claim 1,
The control means includes: a first control mode that maximizes plasma distributed in a region facing the mounting surface of the lower electrode ; and a second control mode that maximizes plasma reaching the inner wall surface of the processing chamber. A plasma processing apparatus having a switch for switching between multiple stages or arbitrarily. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the control means realizes a predetermined plasma distribution corresponding to each of the control modes in the processing chamber by switching a plurality of control modes. The plasma processing apparatus according to claim 3, wherein
The plasma processing apparatus, wherein the control means changes circuit characteristics of the first filter during the process. The plasma processing apparatus according to claim 2, wherein
The sensor detects a value of a current flowing through the first filter;
The control means controls the current value to increase when the first control mode is selected, and when the second control mode is selected, the current value is A plasma processing apparatus which is controlled in a decreasing direction. The plasma processing apparatus according to claim 2, wherein
The sensor detects a voltage value applied to the first filter;
The control means controls the voltage value to decrease when the first control mode is selected, and when the second control mode is selected, the voltage value is A plasma processing apparatus that is controlled in a direction of increasing. The plasma processing apparatus according to claim 2, wherein
The sensor detects the number of ions that reach a predetermined region of the inner wall surface of the processing chamber,
The control means controls the number of ions to decrease when the first control mode is selected, and the number of ions when the second control mode is selected. A plasma processing apparatus that is controlled in an increasing direction. In the plasma processing apparatus of any one of Claims 1-4,
The plasma processing apparatus, wherein the control means controls circuit characteristics of the first filter in accordance with a value obtained by performing arithmetic processing on a detection result output from the sensor. The plasma processing apparatus according to claim 1,
A power source for applying a bias between the connected to the lower electrode and the lower electrode and the upper electrode,
A second filter connected between the upper electrode and the ground, the circuit characteristics of which can be changed;
The plasma processing apparatus, wherein the control means controls a circuit characteristic of the second filter based on a detection result output from the sensor. The plasma processing apparatus according to claim 9, wherein
The sensor detects a value of a current flowing through the second filter;
The plasma processing apparatus, wherein the control unit controls the current value to increase. The plasma processing apparatus according to claim 9, wherein
The sensor detects a voltage value applied to the second filter;
The plasma processing apparatus, wherein the control means controls the voltage value to decrease. The plasma processing apparatus according to claim 9, wherein
The sensor detects the number of ions that reach a predetermined region of the inner wall surface of the processing chamber,
The plasma processing apparatus is characterized in that the control means controls the number of ions to be reduced. The plasma processing apparatus according to claim 9, wherein
The plasma processing apparatus, wherein the control means controls circuit characteristics of the first and second filters in accordance with a value obtained by performing arithmetic processing on a detection result output from the sensor. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the control means appropriately controls circuit characteristics of the first filter so that occurrence of abnormal discharge in the processing chamber is suppressed. The plasma processing apparatus according to claim 9, wherein
The plasma processing apparatus, wherein the control means appropriately controls circuit characteristics of the first and second filters so that occurrence of abnormal discharge in the processing chamber is suppressed. In the plasma processing apparatus of any one of Claims 1-8 and 14,
The plasma processing apparatus, wherein the first filter has a capacitance of 1000 pF or less or an inductance of 5 μH or more. The plasma processing apparatus according to any one of claims 9 to 13 and 15,
The plasma processing apparatus, wherein the first and second filters have a capacity of 1000 pF or less or an inductance of 5 μH or more. The plasma processing apparatus according to any one of claims 9 to 13, 15, and 17,
The first filter includes a first module that blocks passage of a DC component, a second module that can change a circuit constant with respect to the frequency of the AC electric field, and a third module that blocks passage of a frequency component of the bias. A plasma processing apparatus. The plasma processing apparatus according to any one of claims 9 to 13, 15, 17, and 18 ,
The second filter includes a first module that blocks passage of a DC component, a second module that can change a circuit constant with respect to the frequency of the bias, and a third module that blocks passage of a frequency component of the high-frequency electric field. A plasma processing apparatus. The plasma processing apparatus according to claim 18 , wherein
The plasma processing apparatus, wherein the first filter includes a shielding plate that electrostatically or electromagnetically shields between the first and second modules and the third module. The plasma processing apparatus according to claim 19 , wherein
The plasma processing apparatus, wherein the second filter includes a shielding plate that electrostatically or electromagnetically shields between the first and second modules and the third module. A susceptor having a mounting surface that is placed in an airtight processing chamber and places an object to be processed;
  An electric field generating means for exciting the plasma by generating an alternating electric field at a position opposite to the mounting surface of the susceptor;
  A first filter connected between the susceptor and the ground and capable of changing circuit characteristics;
  A sensor for detecting the state of the plasma;
  Control means for controlling circuit characteristics of the first filter based on a detection result output from the sensor;
  In a plasma processing apparatus comprising:
  The first filter includes a first module that blocks passage of a DC component, and a second module that can change a circuit constant corresponding to the frequency of the AC electric field.
  A plasma processing apparatus.

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